Vacuum ultraviolet (VUV) light has important applications in many fields, ranging from device fabrication to photochemistry, from environmental remediation to microscopy and spectroscopy. Methods to produce coherent VUV light frequently utilize high harmonic generation in media such as rare gases or atomic vapors; nonlinear optical crystals that support second harmonic generation into the VUV are quite rare. Here, we demonstrate an all-dielectric metasurface designed for the nonlinear optical generation of VUV light. Consisting of an array of zinc oxide nanoresonators, the device exhibits a magnetic dipole resonance at a wavelength of 394 nm. When excited with ultrafast laser pulses at this wavelength, the second harmonic at 197 nm is readily generated. Manipulation of the metasurface design enables control over the radiation pattern. This work has the potential to open the door toward simple and compact VUV sources for new applications.
Keywords: Second harmonic generation; VUV; ZnO; all-dielectric metasurface; magnetic dipole; nonlinear metasurface; vacuum ultraviolet; zinc oxide.